Structural and functional characterization of genes PYL-PP2C-SnRK2s in the ABA signalling pathway of Cucurbita pepo.

Background: The core regulation of the abscisic acid (ABA) signalling pathway comprises the multigenic families PYL, PP2C, and SnRK2. In this work, we conducted a genome-wide study of the components of these families in Cucurbita pepo.

Results: The bioinformatic analysis of the C. pepo genome resulted in the identification of 19 CpPYL, 102 CpPP2C and 10 CpSnRK2 genes. The investigation of gene structure and protein motifs allowed to define 4 PYL, 13 PP2C and 3 SnRK2 subfamilies. RNA-seq analysis was used to determine the expression of these gene families in different plant organs, as well as to detect their differential gene expression during germination, and in response to ABA and cold stress in leaves. The specific tissue expression of some gene members indicated the relevant role of some ABA signalling genes in plant development. Moreover, their differential expression under ABA treatment or cold stress revealed those ABA signalling genes that responded to ABA, and those that were up- or down-regulated in response to cold stress. A reduced number of genes responded to both treatments. Specific PYL-PP2C-SnRK2 genes that had potential roles in germination were also detected, including those regulated early during the imbibition phase, those regulated later during the embryo extension and radicle emergence phase, and those induced or repressed during the whole germination process.

Conclusions: The outcomes of this research open new research lines for agriculture and for assessing gene function in future studies.